Robert F. Smith, a private equity billionaire and new member of the Giving Pledge. He is pictured at The 2015 Ripple Of Hope Awards in December 2015 in New York City. (Photo by Theo Wargo/Getty Images for RFK Human Rights)

The Giving Pledge, an elite network of big philanthropic givers, has gained 14 new members from 7 countries, including the founder of discount airline easyJet, a Norwegian shipping tycoon, the founder of the world's largest private seed company and an Australian slot machine billionaire. The new members bring the total number of Giving Pledge signatories to 168 from 21 countries, according to an announcement on Tuesday from the Giving Pledge.

Bill and Melinda Gates and Warren Buffett launched the Giving Pledge in 2010 in an effort to get more of the planet’s wealthiest to devote their resources to solving society's problems. Pledge members promise to devote the majority of their wealth to philanthropic causes during their lifetimes or after their death. There is no enforcement mechanism.

“Philanthropy is different around the world, but almost every culture has a long-standing tradition of giving back,” Melinda Gates, co-chair of the Bill & Melinda Gates Foundation, said in a statement. “Bill and Warren and I are excited to welcome the new, very international group of philanthropists joining the Giving Pledge, and we look forward to learning from their diverse experiences.” The newcomers include the first member from Slovenia (Iza and Samo Login), the first from Norway (Kjell Inge Rokke and his wife Anne Grete Eidsvig) and the first from Tanzania (Mohammed Dewji).

Stelios Haji-Ioannou of Cyprus founded discount airline easyJet in 1995. He and his family still own about one-third of the London-listed airline. Forbes estimates his net worth at $1.3 billion. In his Giving Pledge letter, Haji-Ioannou wrote: “My belief is that nobody has a monopoly on good charitable ideas, and the problems in our world will never all go away. So we have to keep helping, within our means, forever...”

Norway’s Kjell Inge Rokke got his start in the fishing business in the U.S., then moved into shipping and offshore drilling through the Aker Group and publicly-traded Aker ASA in Norway. Forbes estimates his net worth at $2.7 billion. “As the lucky ones in life, we have been given much, sacrificed little, and gained a lot,” Rokke wrote in his Giving Pledge letter. “It is a true privilege for our family to reconfirm our commitment to give back by joining The Giving Pledge.”

Leonard "Len" Ainsworth, an Australian billionaire entrepreneur, built two successful slot-machine and gaming machine companies, Aristocrat Leisure and Ainsworth Gaming Technology. Forbes estimates his net worth at $1.2 billion. “As a private person, I prefer to minimise publicity of my philanthropic activities but at the same time realise that setting a positive example is the best way to encourage others to give back,” he wrote in his Giving Pledge letter.

Robert F. Smith founded private equity firm Vista Equity Partners, which invests in enterprise software companies. Forbes estimates his net worth at $2.5 billion. “Potential is no guarantee of progress. We will only grasp the staggering potential of our time if we create onramps that empower ALL people to participate, regardless of background, country of origin, religious practice, gender, or color of skin,” Smith wrote in his Giving Pledge letter. His wife, Hope, is also focusing on causes that support the safety, development and success of foster children and young people.

Harry Stine, a farmer-turned-billionaire, built the largest private seed company in the world, Stine Seed, in Iowa. (See the 2014 Forbes magazine profile of Stine here.) Forbes estimates his net worth at $3.4 billion.

Mohammed "Mo" Dewji, a Tanzanian industrialist, is the first from his country to join the Giving Pledge. Dewji told Forbes in July 2016 that he was joining the pledge.

Another new Giving Pledge member: Dagmar Dolby, the widow of audio pioneer Ray Dolby. Here she speaks at the ceremony honoring Ray Dolby with a star on the Hollywood Walk Of Fame in Hollywood, California on January 22, 2015. (Photo credit MARK RALSTON/AFP/Getty Images)

Dagmar Dolby, the widow of audio systems pioneer Ray Dolby (d. 2013), has been an active philanthropist for many years. She is currently active in supporting programs and research in the brain health and Alzheimer’s field.

Dean Metropoulos, an American private equity billionaire, has turned around a number of consumer goods companies, most recently Twinkies. ( Forbes featured him in a 2015 cover story: "Twinkie's Miracle Comeback".)

The 168 pledgers range in age from 31 to 93. Globally, signatories represent 21 countries: Australia, Brazil, China (mainland and Taiwan), Cyprus, Germany, India, Indonesia, Israel, Malaysia, Monaco, Norway, Russia, Saudi Arabia, Slovenia, South Africa, Tanzania, Turkey, Ukraine, United Arab Emirates, United Kingdom and the United States. In the United States, they are from 27 states and the District of Columbia, with the largest contingents from California and New York.

The full list of the new 2017 Giving Pledge members, and their home countries:

I'm a San Francisco-based Assistant Managing Editor with a focus on wealth. I edit mostly, but also write about how the richest get wealthy and how they spend their time and their money. My colleague Luisa Kroll at Forbes in New York and I oversee the massive reporting effor...